DuraVent DuraStack Installation User Manual
Page 21

NOTE:.DIAGRAMS.&.ILLUSTRATIONS.ARE.NOT.TO.SCALE.
21
BELLOWS EXPANSION JOINT (LB)
1.. .Used.in.diesel.or.turbine.exhaust.installation.for.expansion.and.vibration.
movements.
2.. .Good.for.exhaust.pressure.up.to.60.inches.of.water.column,.it.will.compen-
sate.for.up.to.3”.max.of.expansion..See.table 14.for.maximum.run.with.one.
bellow.
3.. .Bellow.joints.comes.with.a.liner.to.protect.the.bellow.and.to.have.a.smooth.
flow.
4.. .We.suggest.to.always.install.a.12”.length.chimney.downstream.and.upstream.
the.bellow.to.insure.clearance.for.the.liner.and.adding.accessibility.for.sup-
porting..and.guiding..See.Figure 51.‘’bellowjoint’’.for.good.positioning.of.the.
bellow.expansion.joint.
5.. .It.is.of.the.most.important.that.the.bellow.joint.be.properly.supported.and.
guided.in.vertical.and.horizontal.orientation.
6.....Installation.is.done.the.same.way.as.described.in.section.A:.Chimney.and.
fitting.joint.assembly.
Operating temp. [°F]
Max distance with one bellow joint [feet]
700
42.8
800
37.5
900
33.3
1000
30.0
1100
27.3
1200
25.0
1300
23.1
1400
21.4
Table 14
-
Maximum run with bellow between each fixed point
SECTION F - THERMAL EXPANSION
Thermal Expansion :
1.. .When.Model.DIS./.DAS.is.in.use,.thermal.expansion.will.occur.on.
the.inner.flue.and.outer.casing.
2.. .A.good.estimation.for.thermal.expansion.is.approximately.1”.per.
100’.chimney.length.per.100°F.rise.
Thermal expansion [inch] = (length[feet]/100)x(
∆
T[°F]/100)
3.. .Thus,.the.thermal.expansion.is.dependant.on.the.inner.flue.temperature.
and.the.length.of.the.chimney.between.two.(2).fixed.points.
4.. .Good.installation.requires.that.expansion.greater.that.1/4”.must.be.
compensated.with.either.a.bellow.joint.(LB).or.an.adjustable.length.
(LA)...Depending.on.the.pressure.of.the.system.
5.. .Tees.and.elbows.are.not.designed.to.withstand.bending.moment,.
make.sure.to.compensate.thermal.expansion.before.connecting.to.a.
tee.or.a.elbow.
6.. .Expansion.joints.are.not.designed.to.withstand.lateral.forces.so.they.
must.be.accurately.supported.and.guided.
7.. .Because.the.amount.of.outer.casing.movement.is.the.same.as.the.
inner.flue,.the.outer.casing.must.slide.to.avoid.excessive.forces.on.
tees,.elbows.or.fixed.points...To.accommodate.outer.casing.move-
ments,.wall.guide,.floor.guide.and.suspension.bands.must.allow.
movement.of.the.chimney.
8.. .When.supporting.a.system.with.considerable.height.and.thermal.
expansion,. adjustable. lengths. or. bellow. joints. must. be. used. just.
below.every.fixed.support.above.the.first.to.compensate.for.thermal.
expansion..
9....For.engine.or.turbine.exhaust.system.requiring.pressures.up.to.60.
inches.of.water.column,.or.where.the.construction.must.be.abso-
lutely.gas.tight,.all.welded.bellows.length.(LB).are.recommended.for.
expansion.and.vibration.movements.of.the.exhaust.
10...Low.pressure.systems,.such.as.boilers.(up.to.6.inches.water.column),.
can.effectively.use.the.Adjustable.Length.(LA).
11...Spacing.of.guides.and.supports,.when.a.thermal.expansion.part.is.
used,.should.not.be.greater.than.that.specified.in.Section.A,.table 7.
12...Proper.guiding.and.support.of.expansion.parts.often.requires.closer.
spacing.
EXPANSION JOINTS INSTALLATION
Bellows Expansion Joint (LB) and Adjustable Length (LA) in vertical
runs
1.. .A.Bellows.Expansion.Joints.or.Adjustable.Length.installed.vertically.
should.be.installed.directly.below.one.chimney.length.of.the.highest.
support,.between.fixed.points.(see.Figure 51).
2.. .Always.use.Bellows.Expansion.Joints.or.Adjustable.Lengths.between.
fixed.points.when.expansion.is.over.1/4”..See.table 14 and Table 15
for.maximum.run.between.fixed.points.
3.. .Install. proper. guiding. between. fixed. points. when. using. Bellows.
Expansion. Joint. or. Adjustable. Length,. to. allow. chimney. vertical.
movement.due.to.expansion.
Bellows Expansion Joint and Adjustable Length in horizontal runs
1.. .Same.guidelines.apply.as.for.vertical.run.with.respect.to.expansion.
estimate.and.proper.support.and.guiding.with.the.use.of.Bellows.
Expansion.Joint.and.Adjustable.Length.